title: Phencyclidine-induced stereotype in rats: effects of methadone, apomorphine, and naloxone.
abstract: Phencyclidine (PCP) given to male Wistar rats produced hyperactivity and various stereotypic motor behaviors. Methadone, apomorphine, and naloxone were tested for their effects on PCP-induced stereotypy. Methadone (0.5 mg/kg) had no effect on the hyperactivity produced by PCP, but significantly attenuated PCP-induced stereotypy when given both before and after PCP. Low doses of apomorphine were equally effective as methadone in attenuating PCP-induced stereotypy. However, when naloxone was given after methadone or apomorphine to PCP-treated rats, the full PCP-induced stereotypy was again observed. Naloxone pretreatment on doses up to 20 mg/kg was not effective in antagonizing PCP-induced behavioral effects. Methadone and apomorphine antagonism of PCP-induced stereotypy may be mediated by opiate receptors. The results of this study and observations from human studies collectively suggest the possible effectiveness of opiates in treating PCP-induced and functional psychoses.
mesh_terms: D000818:Animals; D001058:Apomorphine / Q000494:pharmacology*; D001923:Brain Chemistry / Q000187:drug effects; D004195:Disease Models, Animal; D006801:Humans; D008297:Male; D008691:Methadone / Q000494:pharmacology*; D009043:Motor Activity / Q000187:drug effects; D009270:Naloxone / Q000494:pharmacology*; D010622:Phencyclidine / Q000037:antagonists & inhibitors* / Q000494:pharmacology; D011605:Psychoses, Substance-Induced / Q000209:etiology; D051381:Rats; D011919:Rats, Inbred Strains; D013239:Stereotyped Behavior / Q000187:drug effects*; D013997:Time Factors
chemical_list: D009270:Naloxone; D010622:Phencyclidine; D001058:Apomorphine; D008691:Methadone